d = {'A':100,'B':90,'C':80};
print(d['A']);
d['D'] = 70;
print(d['D']);

d['D'] = 60;
print(d['D']);

print('E' in d);

i = d.get('E',-1);
print(i);

d.pop('A');#删除一个元素
#set
s = set([1,2,3]);

print(s)
s.add(1);
s.add(4);
print(s)
s.remove(1);
s1 = set([1, 2, 3])
s2 = set([2, 3, 4])
print(s1 & s2);
print(s1 | s2);

a = 'abc';
print(a.replace('a','A'));
print(a);

t = (1,2,3);

dd = {'a':t};
ddd = {t:100};
print(ddd);

